Expandable irrigation controller

ABSTRACT

An expandable irrigation controller for controlling a plurality of watering stations in an irrigation system includes a removable front panel and an inner housing, connected to the front panel. The removable front panel includes a plurality of manual controls operable to input instructions for a watering program, a memory operable to store the input instructions and a controller operable to execute the watering program. The inner housing includes a circuit board including control connectors which are connected electrically to the controller and a station module operable to provide an ON/OFF signal to at least one watering station of the irrigation system. The station module is electrically connected to the circuit board via the control connectors and the ON/OFF signal is provided based on instructions from the controller in accordance with the watering program. The control connectors are positioned in a substantially continuous line extending across the inner housing such that the station module is connectable to the control connectors at substantially any desired location. Multiple modules of different sizes may be mounted in the inner housing as desired. Control information may be provided via a radio frequency supply and received by a radio frequency module to be provided to the station modules and to external station modules in an external housing.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 11/714,463 entitled EXPANDABLE IRRIGATION CONTROLLER filed Mar.5, 2007 which claims benefit of and priority to U.S. Provisional PatentApplication No. 60/778,872 entitled EXPANDABLE IRRIGATION CONTROLLERfiled Mar. 3, 2006, U.S. Provisional Patent Application No. 60/781,630entitled EXPANDABLE IRRIGATION CONTROLLER filed Mar. 13, 2006 and U.S.Provisional Patent Application No. 60/794,266 entitled EXPANDABLEIRRIGATION CONTROLLER, filed Apr. 21, 2006, the entire contents of eachof which is hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an expandable irrigation controller forcontrolling operation of an irrigation system pursuant to a wateringschedule that may be programmed by a user. More particularly, thisinvention relates to an expandable irrigation controller for controllingmultiple irrigation stations.

2. Description of the Related Art

Over the past decade modular expandable irrigation controllers havegained increasing popularity although they have been in commercial usedating back into the 1970's or earlier; i.e. such as the Toro GolfCourse Satellite Irrigation Controller. The base portion of thesecontrollers typically contains the programmable logic portion, ormicroprocessor and user actuated controls.

Each watering station is then preferably controlled by a correspondingmodule that includes electronically controllable station on/offswitching circuitry. The modules are preferably connected to a pluralityof irrigation control valves in the irrigation system at each of aplurality of watering stations. These valves are typically solenoidactivated. Generally, each module can independently control more thanone watering station.

The modules shown in the prior art Toro Golf Course Satellite IrrigationController each controlled 8 stations with four 8-station modulesinstalled and another 4 positions for a total of 8 station modules inthe same weather resistant enclosure. Some other expandable controllersshow various arrangements of “slots” or “cavities” for accommodatingmodules of a selected size.

The modules typically contain pins, sockets, card edge connectors, orsome other standard form of electro-mechanical connectors that allowthem to be inserted into the slots or receptacles in either the housingthat contains the microprocessor or a separate portion connected to themicroprocessor housing. The advantage of this configuration is that thecontroller can be provided with a minimum number of modules suitable forcontrol of the total number of watering stations in the system at first,yet can economically and easily be expanded if the need for morewatering stations later occurs. Thus, for example, an irrigation systemmay have only three zones, requiring only a single station module, whileanother may have twelve stations, which might require four 3-stationmodules. Considerable cost savings are thus achieved. Moreover, if anirrigation system expands after initial installation because thelandscaping has increased, additional station modules can be addedwithout having to replace the entire controller.

Since station output switching circuits may be damaged in service bylightning or over-load current, over time, the damaged circuitry can bereplaced by simply replacing a module without the effort or expense ofreplacing or removing for service the entire irrigation controller.

In the prior art, however, there are slots, cavities or mounting padsfor selected size modules to go into selected locations. Modules of thesame size are often interchangeable in that the “slots”, “cavities” or“pads” are of the same size. However, this means that the modules mustbe installed into slot cavities or onto pads that are large enough toaccommodate the number of watering stations that they will power.Smaller modules would not fit into the slots, cavities etc., or would beloose and not mounted properly, which may affect proper contact. Thus,there is limited flexibility as to the size of the modules, andconsequently, the number of watering stations they may control.

The new Toro TMC-424 controller does not provide for wider modules inorder to accommodate additional terminals for station control, but addsmore rows of terminals on same width station expansion module so thatthey can fit into same slots or cavities. Thus, size of the modules isstill limited.

In some cases, only 2 station module slots or cavities are shown. Thus,to get 8 station outputs or terminals, the customer must purchase 4 twostation modules. This may be more expensive than purchasing 2four-station modules or 1 eight-station module. When additionalexpansion is required, one must add modules of a size allowed for by thepre-existing slots or cavities of the controller housing.

The new Toro Controller TMC-424 uses station expansion modules that fitinto existing sized cavities or slots, but adds more terminals to eachmodule in double rows. However, as noted above, this limits flexibilitywith regard to the size of the modules that may be used to expand thenumber of watering stations controlled by the controller, which mayresult in higher costs.

SUMMARY OF THE INVENTION

In accordance with an embodiment of the present invention, a modularexpandable irrigation controller is provided including controls formanual entry or selection of a watering program and a memory for storingthe watering program. A processor executes the stored watering programand controls one or more station modules, each including a stationmodule circuit for energizing at least one solenoid actuated valve inaccordance with the watering program.

The basic controller may have only a continuous single plug-in areawhere station expansion circuit modules of any of several differentsizes may be installed into the controller in any order as required, notjust into pre-manufactured module size cavities or slots requiringbuying more, smaller modules to get to more stations.

An expandable irrigation controller for controlling a plurality ofwatering stations in an irrigation system in accordance with anembodiment of the present invention includes a removable front panel,the removable front panel including a plurality of manual controlsoperable to input instructions for a watering program, a memory operableto store the input instructions and a controller operable to execute thewatering program. The controller also includes an inner housingconnected to the front panel, the inner housing including a circuitboard including control connectors which are connected electrically tothe controller and a station module operable to provide an ON/OFF signalto at least one watering station of the irrigation system, wherein thestation module is electrically connected to the circuit board via thecontrol connectors and the ON/OFF signal is provided based oninstructions from the controller in accordance with the wateringprogram. The control connectors are preferably positioned in asubstantially continuous line extending across the inner housing suchthat the station module is connectable to the control connectors atsubstantially any desired location

In accordance with another embodiment of the present invention, thecontroller may send out an inquiry signal to the station module prior toenacting control to confirm the presence of the station module based onwhether the station module draws current in response to the inquirysignal.

An expandable irrigation controller for controlling a plurality ofwatering stations in an irrigation system in accordance with anembodiment of the present invention includes a removable front panel,the removable front panel including a plurality of manual controlsoperable to input instructions for a watering program, a memory operableto store the input instructions and a controller operable to execute thewatering program. The expandable irrigation controller also includes aninner housing connected to the front panel. The inner housing includes acircuit board connected electrically to the controller, wherein thecircuit board includes two electrical conductors extending across theinner housing, wherein control information from the controller isencoded for transmission on the two electrical conductors and a stationmodule operable to provide an ON/OFF signal to at least one wateringstation of the irrigation system. The station module is preferablyelectrically connected to the two electrical conductors and the ON/OFFsignal is provided based on the control information from the controllerin accordance with the watering program. The station module ispreferably connectable to the two electrical conductors at substantiallyany desired location.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a front panel of an expandable irrigationcontroller in accordance with an embodiment of the present invention.

FIG. 2 is an illustration of an inner housing of an expandableirrigation controller in accordance with an embodiment of the presentinvention.

FIG. 3 is an illustration of output station modules installed in theinner housing of the expandable controller of FIG. 2.

FIG. 4 illustrates a different arrangement of station modules installedin the inner housing of the expandable irrigation controller of FIGS. 2and/or 3.

FIG. 5 is an illustration of a twist type lock screw.

FIG. 6 is an illustration of an inner housing of an expandableirrigation controller in accordance with another embodiment of thepresent invention.

FIG. 7 is a partial cross section view of a module mounted in the innerhousing of FIGS. 2 and/or 3.

FIG. 8 is an illustration of an inner housing of an expandableirrigation controller in accordance with another embodiment of thepresent invention.

FIG. 9 is an illustration of an inner housing of an expandableirrigation controller in accordance with another embodiment of thepresent invention.

FIG. 9A is an illustration of an inner housing of an expandableirrigation controller in accordance with another embodiment of thepresent invention

FIG. 10 shows a cross-sectional view of a station expansion modulemounted in the inner housing of FIGS. 9 and/or 9A.

FIGS. 11-12 illustrate an inner housing of an expandable irrigationcontroller in accordance with another embodiment of the presentapplication.

FIGS. 13-14 illustrate an inner housing of an expandable irrigationcontroller in accordance with another embodiment of the presentapplication.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a removable front panel 1 of a modular irrigationcontroller 10 in accordance with an embodiment of the present invention.The front panel 1 is preferably removably hinged to the inner housing 2,(see FIG. 2), by hinge pins 6 and 7 which fit into pin holes 8 and 9formed on the inner housing 2. A set of manual actuation controlsincluding, for example, a rotary switch 15, one or more push buttons 16and one or more slide switches 17 may be provided on the panel 1 toallow for inputting instructions or commands to a microprocessor (notshown) that is enclosed in the panel 1. These instructions may be partof a watering program executed by the microprocessor and preferablystored in a memory also provided in the panel 1. An LCD display 18 mayalso be provided to display activities being transacted by theexpandable irrigation controller's microprocessor. The panel 1 ispreferable removably attached to the inner housing 2 (see FIG. 2) suchthat it can be removed, for example, while a watering program is beingentered. Thus, the panel 1 may also include a battery.

The main controller or microprocessor is preferably mounted inside thefront panel 1, as noted above, and is preferably connected via a ribboncable or other connector to the connector socket 21 of the back panelcover 20 of the inner housing 2 (see FIG. 2, for example). The backpanel cover 20 may include the contacts 30 for connection to the stationmodules used to control the water stations. Three different sizedstation modules 31, 32 and 33, are shown installed into the housing 2 inFIG. 3.

The removable front panel 1 of the expandable irrigation controller 10which contains the manual controls 14, 15, 16 and the microprocessor(not shown) is connected to the circuit board 22 covered by the panelcover 20, its power supply 25 and the contacts 30 for the stationmodules via the ribbon cable. The power supply 25 is preferably atransformer connected to the circuit board 22 by transformer wires 26and 27 and terminal screws 28 and 29. Terminal screws 50 and 51 in thecover 20 may be used for connection to a rain switch, if desired, andthe terminal 53 may be used for connection to ground.

FIG. 4 illustrates the inner housing 2 of the expandable irrigationcontroller 100 of FIGS. 2-3 with a different configuration of stationmodules including modules 31, 33 mounted therein. As can be seen in FIG.4, one station module similar to module 31 of FIG. 3 is mounted in thehousing 2 along with three station modules similar to module 33 of FIG.3. As can be seen in FIG. 4, the station modules 33 may be positionedimmediately next to each other, or may be separate from each other andthe module 31. Thus, the versatility of the controller 10 of the presentinvention is clear. As is also clear, different sized modules 31, 33 canbe mounted in the inner housing 2.

Station module 31 is shown with seven terminal contact screws 40-47which may be used for connection to six watering stations. The extraterminal is preferably used as a common return terminal for all of theother watering stations controlled by the controller. A module of thesize of module 31 could also be pre-constructed to provide an output tocontrol a pump start relay or master valve as well, while the other fiveterminals may be connected to individual watering stations via fieldwires (not shown). The station module 32 of FIG. 3 preferably controlsfour watering stations using the four terminals 50-53 (see FIG. 3).Station module 33 preferably controls 3 station modules via theterminals 47-49.

The housing 2 of FIG. 2 shows the mounting and alignment pins 60extending up from the back wall of the housing 2. The station modules,such as station modules 31, 32, 33, may be installed on the mountingpins 60 by aligning a hole 66 in the bottom cover 65 (see FIG. 7, forexample) of each station module (31, 32, 33) with the pin 60 and turningthe top end of the module surface 62 to align with the end surface 63 ofthe cover 20, as shown in FIGS. 2, 3 and 7. The module (31, 32, 33) maythen be pushed down such that the spring contacts 70 contact thecontacts 30 of the circuit board 22. See FIG. 7, for example. FIG. 7illustrates module 32 mounted on a pin 60, however, the other modules 31and 33 are mounted in a similar manner.

The station module (31, 32, 33) may then be locked in place by twistlock screw 10 (see FIG. 5, for example) such that spring contact 70 iscompressed. In a preferred embodiment, the station module is permanentlylocked into place via the screw 10 such that the module cannot be easilyremoved. That is, a locking means of some sort is preferably provided tolock the screw 11 down once it is used to secure the station module (31,32, 33) into place. As a result, the station modules are generally notremovable from the housing 2 once they are installed. Alternatively, themodules may be releasably secured by the screw as well

The twist lock screw 10 engages the underside 67 of the hollow alignmentpins 60 through a keyhole opening 66 in the top of the pin 60. See FIGS.2 and 7, for example. The locking means (not shown) may thus be providedon the hollow side of the pin 60 for example.

FIG. 8 illustrates an inner housing 80 of an expandable irrigationcontroller in accordance with an alternative embodiment of the presentinvention. The housing 80 is preferably connected to the panel 1 of FIG.1 in much the same manner as described above. As illustrated, an outputterminal strip 81 is permanently mounted on the housing's circuit board82. That is, the output terminals 84 that are connected to the wateringstations are permanently mounted in the housing 80, rather than beingmounted on a station module. There are at least two advantages providedby this configuration: (1) the field wiring to the output terminals ofthe expandable irrigation controller, once connected, does not have tobe removed to replace a module, and (2) the control circuitry can beseparated from the power circuitry. The station modules 83 include therelatively expensive power switch that provides the ON/OFF signalprovided to the watering stations controlled by the station module andwhatever other power supply and drive circuitry is required. The stationmodules 83 may include only a relay with its switch contacts forproviding power on and off to the terminals, such as terminal 84, alongthe terminal strip 81. The relay's low voltage, low current actuationcoil can be activated by the output from stepping driver chips that canbe mounted on the circuit board 82 under the back panel cover 85 in FIG.8, for example. Each module 83 may include decoder circuitry forconnection to a serial data output from the irrigation control logiccircuitry (microprocessor) housed in panel 1 (see FIG. 1) and connectedto the back panel circuit board 82 by a ribbon cable or other connector,as is described above.

The circuit board 82 may be made of two separated boards to save circuitboard material, but is shown here for simplicity, as a single board withseparated connections 90 and 91 for the modules. The control connections90 run along the top of the circuit board to allow for control of themodules 83. The output connections 91 run along the bottom of the board82 next to the output terminal strip 81 for power input and outputconnection to the terminal strip 81.

One advantage of this embodiment is that it provides increasedprotection from lightning and increased surge protection of the lowvoltage control elements of the station modules 83 and the irrigationcontroller microprocessor in panel 1, for example. That is, since themodules 83 are physically separated from the terminals 84, there is lesslikelihood that they will be damaged in the event of a lightning strike.

The expansion modules 83 shown in FIG. 8 are shown as controlling twostation terminals 84 each, but could be manufactured for controllingfour, six or eight station output terminals and lined-up with thestation terminals appropriately. Alignment pins (not shown) may beprovided to stand up off the back wall of the housing 80 in a mannersimilar to that of the pins 60 of FIG. 2, for example. The modules 83may be aligned and held in place by a twist lock screw 88 in hole 87 ora continuous channel slot in the back panel of the housing 80 and pushedagainst each other to stack side by side. Terminal 89 could, forexample, be connected as a common ground return from all of the wateringstations.

The microprocessor may determine which of the station modules 83 areinstalled by sensing which outputs of the main controller circuit drawcurrent or feed back logic on a serial port trace connection between thecontrol logic (microprocessor) in panel 1 and that contained in each ofthe modules 83. There are a number of ways to accomplish this that arewell known in the art, and are not discussed in further detail herein.However, the simple concept of having the controller (microprocessor)make an inquiry whenever it is going to execute an irrigation program bya quick cycle through each station to sense which outputs of the maincontroller draw current is a simple and unique concept. That is, priorto implementing a watering program, the microprocessor may determinewhich connectors to the station modules are drawing current.

Another embodiment of a housing 95 for an expandable irrigationcontroller in accordance with an embodiment of the present invention isdescribed with reference to FIG. 9. In FIG. 9, the power anddistribution circuit board 99 is shown installed as standing in slots 91a and 92 that extend out of the back of the housing 95. Circuit board 99has a right angle terminal block 93 wave soldered onto it forconnections such as the terminals similar to the terminals 28, 29, 50,53 and 51 of FIG. 2, previously described. A ribbon cable connector 94can be wave soldered onto the circuit board 99 for connection to thecontrol logic (microprocessor) housed in the removable panel 1 of FIG.1.

The power and station expansion module circuit board 99 can beconfigured to only have two conducting traces 96 and 97 running acrossthe irrigation controller housing 95 on the circuit board 99 that carrythe 60 or 50 Hz, 24 volt power for actuating the irrigation systemcontrol valve solenoids. These two valve actuation power traces 96, 97can also have high frequency serial control data optically, radiofrequency or capacitively coupled onto them. Each module 100 preferablyincludes not only the switch circuitry for controlling the ON/OFF signalprovided to the terminals, but also a decoder chip or circuit fordecoding the high frequency serial data which tells each module 100 thatit is plugged into the circuit board 99 and when to turn ON one of thewatering stations it controls. Such “two wire” control electroniccircuits are known in the electrical arts and are not described infurther detail herein. However, it is believed that the use of suchcircuits has not previously been disclosed or suggest for use inirrigation controllers as described herein.

The modules 100 can be of any size and their output terminals may bepositioned anywhere. The modules 100 may be positioned in the primaryhousing 95, or in another external housing (not shown) which ispreferably configured in the same manner as housing 95. This additionalhousing is referred to as housing 95B for the sake of convenience.

The additional housing 95B may be powered and may include modulessimilar to the station modules 100 enclosed therein which are preferablyconnected to this power. Circuit board 99B of the housing 95B ispreferably controlled by the microprocessor of the panel 1 connected tothe housing 95.

The expander module 150 in FIG. 9 is shown connected to the circuitboard 99 of the housing 95. The module 150 is preferably operable toprovide two wire power and control signals via the two wire connection210, 152 to the housing 95B, for example. In this configuration thehousing 95B need not have a transformer power supply of its own.

The connection to circuit board 99B need only be two conductors toprovide power and control to the additional external modules in housing95B (presuming a 24 volt solenoid actuation signal). If desired,additional external housings may be provided and interconnected in asimilar manner. Alternately, the additional module housing 95B may becoupled to the housing 95 by a radio frequency module 150 a, forexample, as illustrated in FIG. 9A. The housing 95 of FIG. 9A issubstantially similar to that of FIG. 9 except that the radio frequencymodule 150 a replaces the expander module 150. This module 150 a neednot include any terminals since it is unnecessary to connect this moduleto any watering stations itself. However, this module is preferablyconnected to the two traces 96, 97 of the power and control circuithouse 99 by being plugged into the circuit board 99, for example, asillustrated in FIG. 10. The additional irrigation housing 99B referredto above may be linked to the housing 99 by radio frequency, as notedabove, provided that it includes its own power source, such as atransformer. Other external housings may be similarly linked to housing99, if desired, as well. The radio frequency module 150 a may be pluggedinto the circuit board 99 for electrical connection to the traces 96, 97as illustrated in FIG. 10. Preferably, the radio frequency module 150 ais a transmitter/receiver (transceiver) module and does not require anyoutput terminals since it is not connected to a watering station. Poweris provided by the traces 96, 97 which also provide a link to the traces96, 97 such that control information received by module 150 d, that maybe provided from a radio frequency source, such as a separate hand heldremote, for example, is provided to all modules connected to the traces96, 97. The module 150 a also transmits the control information toexternal housings such as housing 95B, for example, to provide controlinformation to them as well. That is, a radio frequency source (notshown) may be provided to send control signals to the module 150 a whichmay be linked to the traces 96, 97 such that the control signals may besent to other modules in housing 95 and may be transmitted to externalhousings, such as housing 95B, for example, to control all of themodules. The radio frequency source may be an external or handhelddevice or may be installed in the panel 1, if desired. Controlinformation may also be provided from the microprocessor in panel 1, forexample, and transmitted to the external housing 95B if desired as well.

The two wire type station modules 100 mentioned above, preferablyinclude decoder setting dials 110 and 115 to indicate which station theyare turning on and which irrigation enclosure housing 95, 95B etc. theyare in. For example, the dials may be used to indicate that the moduleis positioned in housing 95 rather than housing 95B. The second dial 115can be eliminated if the number of stations to be controlled is smallenough to be represented on a single selection dial 110. Theconfiguration shown in FIG. 8, where the out terminal strip 81 ismounted in housing 80 can be applied to these two wire control modules100, if desired.

A cross sectional view of a module 100 being plugged onto the circuitboard 99 is shown in FIG. 10. The spring contacts 120 and 121 of themodule 100 are shown pressing on conducting traces 96 and 97 of thecircuit board 99. The module contacts are preferably in a slot 130across the bottom of each module 100. There can be a second slot 140across the bottom of each module 100 for alignment and to provide spacefor the retention screw 200 in retention slot 210 to secure the moduleto the housing 95.

FIGS. 11-12 illustrate another embodiment of an inner housing of anexpandable irrigation controller in accordance with an embodiment of thepresent application. The controller of FIGS. 11-12 is similar to that ofFIG. 2, for example, and common reference numerals are used to refer tocommon components.

In FIG. 11, housing 2 includes 4 modules 181, 182 a, 182 b, 182 cmounted therein. As illustrated, while the modules 182 a, 182 b, 182 cinclude terminals for connection to the same number of wateringstations, however, these modules are not interchangeable. The panelcover 20 of the housing 2 includes a plurality of slots 185. Each of themodules 182 a, 182 b, 182 c includes a protrusion 184 a, 184 b, 184 c,respectively, that fits into one of the slots 185 on the panel cover 20.As a result, the modules 182 a, 182 b, 182 c are not interchangeablewith one another. FIG. 12 illustrates the modules of FIG. 11repositioned so that they are not mounted in order to illustrate how theslots 185 and the protrusions 184 a, 184 b and 184 c are lined up priorto mounting.

FIGS. 13-14 illustrate another embodiment of an expandable irrigationcontroller in accordance with an embodiment of the present application.The controller of FIGS. 13-14 is similar to that of FIGS. 1-3, forexample, and common reference numerals are used to refer to commoncomponents. As is best illustrated in FIG. 14, the modules 31, 32, 33,34 are mounted in the housing 2 and are secured in place by theresilient fastening tabs 200 positioned on the top surface of each ofthe modules. The tabs 200 preferably protrude upward slightly. However,when the modules are mounted in the housing 2, as illustrated in FIG.13, the tabs 200 are depressed so that each module slides under thepanel cover 20. The tabs 200 then protrude upward to engage a lip (notshown) on the bottom surface of the panel cover 20 to prevent removal ofthe modules from the housing 2. The tabs 200 include a portion 200 athat extends slightly outward from the cover 20 when the module ismounted in the housing 2. This portion 200 a can be depressed to allowfor removal of the modules from the housing 2. It is noted that themodules 31, 32, 33, of FIGS. 11-12 may also include similar locking tabsif desired.

Although the present invention has been described in relation toparticular embodiments thereof, many other variations and modificationsand other uses will become apparent to those skilled in the art. It ispreferred, therefore, that the present invention be limited not by thespecific disclosure herein, but only by the appended claims.

1. An expandable irrigation controller for controlling a plurality ofwatering stations in an irrigation system comprises: a removable frontpanel, the removable front panel comprising: a plurality of manualcontrols operable to input instructions for a watering program; a memoryoperable to store the input instructions; and a controller operable toexecute the watering program; and an inner housing, connected to thefront panel, the inner housing comprising: a circuit board connectedelectrically to the controller, wherein the circuit board includes twoelectrical conductors extending across the inner housing, whereincontrol information from the controller is encoded for transmission onthe two electrical conductors; and a station module operable to providean ON/OFF signal to at least one watering station of the irrigationsystem, wherein the station module is electrically connected to the twoelectrical conductors and the ON/OFF signal is provided based on thecontrol information from the controller in accordance with the wateringprogram, and wherein the station module is connectable to the twoelectrical conductors at substantially any desired location.
 2. Theexpandable irrigation controller of claim 1, wherein the station modulefurther comprises: control contacts operable to electrically connect thestation module to the two electrical conductors; a decoder circuitoperable to decode the control information from the controller sent tothe station module by the two electrical conductors; a switching circuitoperable to provide the ON/OFF signal for the watering station based onthe decoded information; and a terminal connected the watering stationto send the ON/OFF signal to the watering station.
 3. The expandableirrigation controller of claim 2, further comprising: an expander modulemounted in the inner housing and connected to the two electricalconductors, wherein the expander module is operable to pass the controlinformation from the two electrical conductors to an external housing inwhich one or more external station modules are mounted, such that thecontrol information from the controller is used to control the externalstation modules.
 4. The expandable irrigation controller of claim 3,wherein the station module further comprises a setting dial rotatablebetween a plurality of positions, wherein a specific position of thesetting dial indicates the watering station controlled by the stationmodule and whether the station module is positioned in the externalhousing.
 5. The expandable irrigation controller of claim 2, furthercomprising: a radio frequency module connected to the two electricalconductors and operable to send and receive radio frequency signals,wherein the radio frequency module sends a control radio frequencysignal to an external housing in which one or more external stationmodules are mounted, such that the control information in the controlradio frequency signal is used to control the external station modules.6. The expandable irrigation controller of claim 5, wherein the controlinformation is received from the controller via the two electricalconductors.
 7. The expandable irrigation controller of claim 5, whereinthe control information is received from a remote radio frequencysource; and wherein the radio frequency module links the controlinformation to the two electrical conductors such that the controlinformation is provided to the station module in the inner housing andis included in the control radio frequency signal.
 8. The expandableirrigation controller of claim 7, wherein the housing further comprisesa second station module connected to the two electrical conductors,wherein the second station module is operable to control a wateringstation based on the control information linked to the two electricalconductors b the radio frequency module.